Plants naturally produce an assortment of fatty acids and synthesize a wide assortment of lipids, including mono-, di-, and tri-acylglycerols, phospholipids, glycolipids, and others, from the fatty acids produced by the plants. The specific assortment of lipids made by any particular plant is determined by both the genotype of the plant and the plant's response to environmental factors such as heat, cold, and drought. However, regardless of the environmental conditions a plant is faced with, a plant can never produce a fatty acid or lipid composition for which it does not have the necessary biochemical machinery.
Recently, there has been an increasing interest in reducing the content of saturated fatty acids in food for diet and health purposes. Medical and nutritional research continues to indicate that unsaturated fatty acids, such as those found in oilseed plants, are important components of diets for a variety of reasons. For example, certain monounsaturated fatty acids, such as palmitoleic acid, have been implicated in lowering the risk of cardiovascular and cerebrovascular diseases, in the regulation of immuno functions, and in the attenuation of inflammations. Efforts have therefore been initiated to develop oilseed varieties and plants which yield oils with higher monounsaturated fatty acid contents. However, the traditional methods of genetic modification of plants have involved recombination processes which are typically directed by the plant breeder at a whole plant level, and only produce incremental improvements in oil content and composition by optimizing the native biochemistry of a particular plant species, rather than considerably augmenting or introducing a biochemical pathway.
Further, even when traditional plant breeding methods are successful in altering the fatty acid composition of a particular plant variety, the native biochemical pathways of a plant will still generally exhibit all of their traditional characteristics and limitations. For example, the fatty acid compositions of many oilseed crops have been improved by plant breeding to include a higher content of unsaturated fatty acids. However, these oilseed crops continue to exhibit the usual response to environmental conditions such as a tendency to produce a higher percentage of saturated fatty acids under warmer growing conditions and a higher percentage of unsaturated fatty acids under cooler growing conditions, thus making the reliable production of oilseeds having a particular fatty acid composition difficult.
Accordingly, there remains a need in the art for compositions and methods useful for producing monounsaturated fatty acids.